The primary objective of the Biostatistics, Epidemiology and Administrative Core is to maintain a high level of statistical competency and uniform standards of measurements for the research projects and to administer the overall program project. This core will perform data management and analysis for the projects and other core. A relational database system is used to manage the data and increase the efficiency and accuracy of data flow. In addition, it will be responsible for the determinants of bone mass, anthropometrics, dietary intake of nutrients, and physical activity levels, as needed by the four projects. Research assistants performing anthropometric measurements will be retrained regularly. Individual dietary intake of calcium and caffeine nutrients will be quantified by the use of food frequency questionnaires. Questionnaires will be used to illicit activity levels from adults and children. Bone mass measurements for all projects will be performed by experienced technicians, using x-ray absorptiometry for vertebral, hip and total body scans as well as ultrasound measurements at the os calcis. Quality control experiments will be performed regularly. The Core will be responsible for the financial and overall administration of the entire program project.